public void PopulateAssignedCategoryData(Fatu_Maria_Lab8Context context,
Book book)
{
var allCategories = context.Category;
var bookCategories = new HashSet<int>(
book.BookCategories.Select(c => c.BookID));
AssignedCategoryDataList = new List<AssignedCategoryData>();
foreach (var cat in allCategories)
{
AssignedCategoryDataList.Add(new AssignedCategoryData
{
CategoryID = cat.ID,
Name = cat.CategoryName,
Assigned = bookCategories.Contains(cat.ID)
});
}
}
public void UpdateBookCategories(Fatu_Maria_Lab8Context context,
string[] selectedCategories, Book bookToUpdate)
{
if (selectedCategories == null)
{
bookToUpdate.BookCategories = new List<BookCategory>();
return;
}
var selectedCategoriesHS = new HashSet<string>(selectedCategories);
var bookCategories = new HashSet<int>
(bookToUpdate.BookCategories.Select(c => c.Category.ID));
foreach (var cat in context.Category)
{
if (selectedCategoriesHS.Contains(cat.ID.ToString()))
{
if (!bookCategories.Contains(cat.ID))
{
bookToUpdate.BookCategories.Add(
new BookCategory
{
BookID = bookToUpdate.ID,
CategoryID = cat.ID
});
}
}
else
{
if (bookCategories.Contains(cat.ID))
{
BookCategory courseToRemove
= bookToUpdate
.BookCategories
.SingleOrDefault(i => i.CategoryID == cat.ID);
context.Remove(courseToRemove);
}
}
}
}
